Question: Which of the following numbers is a multiple of 8? ${47,64,69,79,97}$
The multiples of $8$ are $8$ $16$ $24$ $32$ ..... In general, any number that leaves no remainder when divided by $8$ is considered a multiple of $8$ We can start by dividing each of our answer choices by $8$ $47 \div 8 = 5\text{ R }7$ $64 \div 8 = 8$ $69 \div 8 = 8\text{ R }5$ $79 \div 8 = 9\text{ R }7$ $97 \div 8 = 12\text{ R }1$ The only answer choice that leaves no remainder after the division is $64$ $ 8$ $8$ $64$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $8$ are contained within the prime factors of $64$ $64 = 2\times2\times2\times2\times2\times2 8 = 2\times2\times2$ Therefore the only multiple of $8$ out of our choices is $64$. We can say that $64$ is divisible by $8$.